Move Fast and Consumer Driven Contract Test Things

At SoundCloud, we've found that teams move faster when we've moved away from a monolith architecture to one based around microservices. Unfortunately, this new type of architecture has been prone to cascading failures when breaking changes go unnoticed in one of our services' API's. These failures have had a devastating impact on our system's uptime, but we've found that we can mitigate some of this risk by introducing consumer driven contract tests.

Consumer driven contract tests allow each consumer service and client to define their expectations and interactions with each provider service upstream, and for provider services to verify all of these contracts as part of their build pipeline. Breakage avoided.

In this talk we’ll go through SoundCloud’s process of breaking the monolith into microservices, then see how PACT-based contract tests were introduced, and discuss some of the challenges of adopting such tests in an already-established microservices culture.